We propose a coordinated program of research aimed at the discovery of new tools and tactics for the selective control of insect pests and vectors of disease. In collaboration with three postdoctoral associates and two graduate students the investigation will be carried out on the "tobacco hornworm" (Manduca sexta) -- a large lepidopteran cultured throughout the year on a synthetic diet. Our central objective is to identify Insect Growth Regulators which, unlike the presently available juvenile hormone analogs, can derail the growth of immature larval insects. There are cogent reasons for believing that anti-insect-hormones will have this ability. BIBLIOGRAPHIC REFERENCES: Cherbas, P., L. Cherbas and C.M. Williams, 1977. Induction of acetylcholinesterase activity by Beta-ecdysone in a Drosophila cell line. Science, in press. Williams, C.M., 1977. Anti-juvenile hormone effects of a diffusible agent that inhibits the corpora allata. In: Natural Substances and the Protection of Plants, Pontifical Scripta Varia No. 41, in press.